Enzymatic process for the enantiomeric resolution of amino acids

Abstract

An enzymatic process permitting the enantiomeric resolution of amino acids is provided. More specifically, this process for separating the enantiomers of an amino acid comprises treating a racemic mixture of the amino acid with glutaric anhydride and then with the enzyme glutaryl-7-ACA acylase so as to recover one of the enantiomers of the amino acid, the other enantiomer remaining in the form of the corresponding glutarylamide derivative.

1. A process for separating the enantiomers of an amino acid, comprising:
 treating a racemic mixture of the amino acid with glutaric anhydride to form glutarylamide compounds of the enantiomers; and  
 treating the glutarylamide compounds of the enantiomers with glutaryl-7-ACA acylase to recover one of the enantiomers of the amino acid, the other enantiomer remaining in the form of a glutarylamide compound.  
 
     
     
       2. The process of  claim 1 , wherein the amino acid has the formula (I): 
                 
 
       in which
 n is an integer chosen from 0, 1, 2, 3, 4, 5, and 6,  
 R represents a hydrogen atom or an optionally substituted radical chosen from alkyl, alkene, alkyne, cycloalkyl, aryl, condensed polycyclic hydrocarbon, and heterocycle,  
 and R′ represents an optionally substituted radical chosen from alkyl, alkene, alkyne, cycloalkyl, aryl, condensed polycyclic hydrocarbon, and heterocycle, or an oxy, thio, sulphoxide or sulphonyl radical substituted by an optionally substituted radical chosen from alkyl, aryl, cycloalkyl, and heterocycle.  
 
     
     
       3. The process of  claim 2 , wherein n is an integer chosen from 0, 1, 2, and 3, and R represents a hydrogen atom, an alkyl radical, or an aryl radical. 
     
     
       4. The process of  claim 2 , wherein n is an integer equal to 0, 1 or 2, R represents a hydrogen atom or an alkyl radical, and R′ is chosen from optionally substituted heterocycles and aryls. 
     
     
       5. The process of  claim 1 , wherein the glutaryl-7-ACA acylase is in soluble form. 
     
     
       6. The process of  claim 1 , wherein the glutaryl-7-ACA acylase is in immobilized form. 
     
     
       7. The process of  claim 1 , wherein an amount of enzyme employed relative to a total amount of initial amino acid substrate is between about 1 and 100 units per mmole of the initial amino acid substrate. 
     
     
       8. The process of  claim 2 , wherein an amount of enzyme employed relative to a total amount of initial amino acid substrate is between about 1 and 100 units per mmole of the initial amino acid substrate. 
     
     
       9. The process of  claim 1 , wherein the treatment is carried out in a buffered aqueous medium. 
     
     
       10. The process of  claim 9 , wherein the buffered aqueous medium comprises an aqueous buffer having a concentration of between about 10 mM and 200 mM and is chosen from acetate buffers that are used at a pH of between about 5 and 6.5, phosphate buffers that are used at a pH of between about 6.5 and 8, and pyrophosphate buffers that are used at a pH of between about 8 and 9. 
     
     
       11. The process of  claim 1 , wherein the racemic mixture has a pH that is monitored and adjusted to between about 6 and 9. 
     
     
       12. The process of  claim 1 , wherein the treatment of the amino acid with glutaric anhydride occurs at a temperature of between about 20° C. and 40° C. 
     
     
       13. The process of  claim 1 , wherein the treatment with the glutaryl-7-ACA acylase occurs at a temperature of between about 10° C. and 50° C. 
     
     
       14. The process of  claim 1 , wherein the treating lasts between about 1 hour and 100 hours. 
     
     
       15. The process of  claim 1 , further comprising separating (R) and (S) enantiomers. 
     
     
       16. The process of  claim 15 , wherein the separation of the (R) and (S) enantiomers is carried out by filtration, extraction, chromatography, or crystallization. 
     
     
       17. The process of  claim 15 , wherein the separated enantiomer remaining in the form of the glutarylamide compound is hydrolyzed so as to recover the corresponding amino acid in enantiomeric form. 
     
     
       18. The process of  claim 16 , wherein the separated enantiomer remaining in the form of the glutarylamide compound is hydrolyzed so as to recover the corresponding amino acid in enantiomeric form. 
     
     
       19. A process for separating enantiomers of an amino acid, comprising:
 treating a racemic mixture of the amino acid with glutaric anhydride to form glutarylamide compounds of the enantiomers;  
 treating the glutarylamide compounds of the enantiomers with glutaryl-7-ACA acylase to recover one of the enantiomers of the amino acid, the other enantiomer remaining in the form of a glutarylamide compound; and  
 then separating the two enantiomers.  
 
     
     
       20. A process for separating enantiomers of an amino acid, comprising:
 treating a racemic mixture of the amino acid with glutaric anhydride to form glutarylamide compounds of the enantiomers;  
 treating the glutarylamide compounds of the enantiomers with glutaryl-7-ACA acylase to recover one of the enantiomers of the amino acid, the other enantiomer remaining in the form of a glutarylamide compound;  
 then separating the two enantiomers; and  
 hydrolyzing the enantiomer remaining in the form of the glutarylamide compound so as to recover the corresponding amino acid in enantiomeric form.